Pakistan’s media regulator has banned Aamir Liaquat Husain, one of the country’s best known TV hosts, over alleged hate speech and incitement to violence, after he made comments on his show that activists warned could threaten their safety.

The Pakistan Electronic Media Regulatory Authority said Thursday Mr. Husain “willfully and repeatedly” made derogatory remarks and accused various people of being “anti-state and anti-Islam.” Mr. Husain, who hosts a regular show on the Bol News channel, had accused activists who went missing earlier this month--and their supporters--of blasphemy and anti-Pakistan activities.

Mr. Husain, who is also executive president at Bol News, denied the charges in a broadcast Thursday night. "I say with responsibility and love, whatever I said was according to the 1973 Constitution of Pakistan and the Quran," he said.

At least four liberal activists known for their vocal criticism of the country’s security policies and opposition to religious extremists disappeared in Pakistan earlier this month. No law enforcement or intelligence agency, or militant group, has said the activists are in their custody. Pakistan’s government has said it is conducting a thorough investigation.

Mr. Husain’s broadcasts over the past two weeks echoed an online campaign, conducted through several hardline Pakistani social media accounts, which accuses the missing activists of being blasphemers and traitors to Pakistan, charges denied by their supporters.

Blasphemy is illegal in Muslim-majority Pakistan, and carries a maximum death penalty under the law. While the state has never executed anyone convicted of blasphemy against Islam or its holy figures, vigilantes and mobs have killed dozens in recent years over allegations.

The accusations this month against the missing activists endanger their lives as well as the lives of their families and supporters, fellow activists said. Last year, two Pakistani TV hosts were banned for what the regulator described as “irresponsible” discussions on blasphemy.

Mr. Husain shot to fame in the early 2000s as an eloquent televangelist, first hosting an Islamic show and then branching out into variety shows that dominated ratings.

The ban this week on Mr. Husain isn’t his first brush with controversy. In 2008, he was criticized for saying members of the Ahmadiyya minority community deserved to be killed for being apostates.

On his current show on Bol News, Mr. Husain has regularly accused other media executives, TV channels, and activists of being traitors and agents of India, Pakistan's neighbor and rival.

Thursday night, defying the regulator’s ban on his show, Mr. Husain appeared on Bol News, claiming Pakistan’s media regulator had banned him to please its “Indian masters”, as a “present” to Indian Prime Minister Narendra Modi on India’s Republic Day. He said he was unfairly accused of hate speech, and intends to start legal action against the ban, as well as those running a “campaign of propaganda and hate” against him.

Pakistan’s media regulator had warned that the transmission of Bol News will be suspended if it doesn’t comply with the ban.

Authorities said Friday that Bol News has seven days to explain why it didn't comply with the order, or face losing its broadcasting license.